JP2002118757A - Data compression/expansion method and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data compression/expansion method that allows a hardware circuit to easily compress/expand data. SOLUTION: First data are acquired, and when the first data are specific data, data denoting a consecutive number of succeeding specific data are acquired, and the addresses of the specific data are summed. When the first data are other than the specific data, a block of the other data are expanded through the use of the data denoting the consecutive number. Since only non- printed data, such as specific data that are almost consecutive and make up most of print data have only to be expanded, the processing is much simplified, in comparison with a conventional method and the hardware circuit can readily expand the data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for compressing and decompressing data used in a computer system and a printer using the method, and more particularly to a method for compressing and decompressing data which can be easily realized by hardware. Regarding a printer that uses that method.

[0002]

2. Description of the Related Art FIG. 5 is a schematic block diagram showing a general computer system in which a personal computer (hereinafter, referred to as a PC) as a host and a printer are connected. PC via image scanner (not shown)
The graphics data taken into the PC 100 is PC1
Printer 200 on the printer 200
Is converted into interpretable data (control command and print data) and compressed.

The control command and print data are transmitted to a PC
An I / F unit 106 of the PC 100 while being managed by an operating system (hereinafter, referred to as OS) 104 on the PC 100
To the printer 200 via the connection cable 115.

[0004] The control command and the print data are received by the data receiving unit 222 in the I / F control unit 220 of the printer 200, and are stored in the reception buffer memory unit 231 of the printing unit 230. The control command and the print data are interpreted by the command interpreting unit 233, and are expanded into image data for printing by the image data expanding unit 235.

[0005] Thereafter, printing is executed by the print processing execution unit 237 based on the print image data.
The status of the printer, such as the printer status, is managed in real time by the status confirmation unit 239 in the printing unit 230, and the data transmission unit 22 in the I / F control unit 220
4 to the PC 100 as a host.

FIG. 6 is a diagram showing a specific example for explaining a conventional data compression method. In the pre-compression data in this example, five “00h” s continue, and then “41h” and “4h”.
2h, followed by three consecutive “43h.” In such pre-compression data, the consecutive data “00h” and “43h” are compressed to become post-compression data.

That is, the compressed data indicates that the first data “FCh” has five next data “00h”, and the next data “01h” has uncompressed data “41h” and “42h”. ", And the next data" FEh "contains the next data" 43h ".
It is configured to indicate that there are multiple items.

FIG. 7 is a schematic block diagram showing a data expanding function in a conventional printer. Receive buffer 2
The data stored in 40 is read and processed by the CPU 250 byte by byte, and the processed data is written to the image buffer 260 byte by byte. That is, in the CPU 250, the header data is analyzed by the header data analysis unit 251, and the data transfer unit 252 performs block transfer or continuous data development based on the analysis result.

An operation example of such a configuration will be described with reference to a flowchart of FIG. First, header data is obtained, and it is determined from the header data whether or not the data is continuous data (steps S1 and S2). If the data is continuous data, expanded data is obtained, and it is determined whether the expanded data is “00h” (step S3,
S4). If the data to be developed is "00h", the address is added (step S5), and the data to be developed is "00h".
If it is not "h", data for the continuous number is developed (step S6).

On the other hand, if the data is not continuous data in step S2, the data is expanded into blocks (step S2).
7). Next, it is determined whether or not raster development has been completed (step S8). If raster development has not been completed, the process returns to step S1 to repeat the above-described processing. finish.

For example, in the case of the compressed data shown in FIG. 6, first, the first underlined first byte header data "FC
The next data is acquired because "FCh" indicates that there are five consecutive data, and the next data is "00h", so that the address addition is performed. Next, the first underlined header data "01h" of the second underlined part is obtained.Since this "01h" indicates that two uncompressed data are discontinuous, each data "01h" is obtained. 41h "and" 42h "are expanded into blocks.

Finally, the first underlined header data "FEh" of the third underline is obtained. Since this “FEh” indicates that there are three next data in a row, the next data is acquired. And the next data is "43h"
Therefore, data development is performed for the continuous number. As described above, the data can be expanded to the pre-compression data shown in FIG.

[0013]

The above-described conventional data compression / decompression method focuses on the fact that a large number of "00h" data are usually continuous in the print data, and moves the decompression destination address. This enables high-speed deployment.

However, since compressed and uncompressed data are mixed in the compressed data, the step S shown in FIG.
It cannot be determined whether the address addition of 5 or the data writing of steps S6 and S7 is performed in the latter half of the process. For this reason, data compression / expansion by software is possible without any problem, but data compression / expansion by hardware cannot be performed simply, and there is a problem that implementation is difficult.

The present invention has been made in view of the above-mentioned various problems, and has as its object to provide a data compression / decompression method and a data compression / decompression method capable of easily performing data compression / decompression by hardware. It is to provide a printer that uses the method.

[0016]

In order to achieve the above object, according to the present invention, in a method for compressing data, when specific data is continuous, one specific data and data representing the number of continuous data are arranged. When data other than the specific data is continuous, data compression is performed by arranging data representing the number of continuations and data other than the specific data. The specific data is, for example, non-print data that occupies most of the print data and is almost continuous, and only the non-print data is compressed. Compression can be easily achieved.

In order to achieve the above object, the present invention provides:
In the method of expanding data, first data is obtained, and when the first data is specific data, data representing the number of continuous next specific data is obtained and address added, and the first data is obtained. Is data other than the specific data, the data is developed by performing block development on the continuous number of data represented by the data. Since only the non-print data that occupies most of the specific data, for example, the print data and that is almost continuous, needs to be expanded, it is much simpler than before, and the data can be easily expanded by hardware. Can be.

Further, in order to achieve the above object, the present invention provides:
An interface for receiving data from the host,
In a printer including a printing unit that performs a predetermined print process based on data received from the host, the first data among the data received from the host is obtained, and when the first data is specific data, By obtaining data representing the number of consecutive specified data and adding an address, and when the first data is data other than the specified data, by expanding blocks of data corresponding to the number of consecutive data represented by the data, A data expanding means for expanding data is provided. When the specific data is continuous, the data received from the host arranges one piece of the specific data and data indicating the number of consecutive data, and when data other than the specific data is continuous, the number of consecutive data is counted. And data other than the specific data are arranged in a data compression.

Since only the non-print data which occupies most of the print data which is the specific data and which is almost continuous need only be developed, it is very simple compared with the related art, for example, a semiconductor integrated circuit (ASIC) for a specific application. It is possible to easily realize data expansion on hardware such as. Therefore, the compressed print data received from the host can be expanded at a high speed, and the printing speed can be improved.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing an overall configuration of a printer according to an embodiment of the present invention. The printer 2 includes a printer controller 10 and a print engine 2
0.

The printer controller 10 has an interface (hereinafter referred to as “host I / F”) 1 for receiving a print command and print data from the host computer 1.
1, a RAM 12 for storing various data and the like, a ROM 13 for storing various data processing routines and the like,
And a CPU 14.

Further, a print control circuit for performing internal processing for each type of I / F, which will be described later, at high speed in hardware, sending head data and the like to the print head 22 side, and various motor drivers Application Specific Semiconductor Integrated Circuits (Applied Semiconductor)
r Integrated Circuit, hereafter,
An “ASIC”) 15 and an interface (hereinafter, “mechanical I / F”) 16 for transmitting image data, drive signals, and the like to the print engine 20 are provided.

Host I / F 11, RAM 12, ROM 1
3, CPU 14, ASIC 15, mechanical I / F 16, etc.
They are interconnected by a bus 17. Host I / F1
1 receives a print command and print data from the host computer 1. The RAM 12 includes a reception buffer 12
A, the image buffer 12C, the work memory 12B and the like.

The reception buffer 12A has a host I / F 1
1 temporarily stores the print command and print data from the host computer 1 received. In the image buffer 12C, for example, image data in a raster graphics format after analyzing the print command and the print data is developed.

The ROM 13 stores various control programs executed by the CPU 14 and the like. This program includes a main program 13a as shown in FIG.
And an interrupt processing program 13b. ROM1
Reference numeral 3 also stores font data and graphic functions (not shown), various procedures, and the like.

The print engine 20 includes a print head 22
, A carriage mechanism 24, and a paper feed mechanism 26. The paper feed mechanism 26 includes a paper feed motor, a paper feed roller, and the like, and sequentially feeds a print storage medium such as recording paper to perform sub-scanning. The carriage mechanism 24 includes a carriage on which the print head 22 is mounted, a carriage motor for moving the carriage via a timing belt or the like, and causes the print head 22 to perform main scanning. The print head 22 has, in the sub-scanning direction, an ink jet nozzle row for each color composed of, for example, 64 nozzles, and discharges ink droplets from each nozzle at a predetermined timing.

FIG. 2 is a diagram showing a specific example corresponding to FIG. 6 for explaining a data compression method according to the embodiment of the present invention. As shown in FIG. 6, the pre-compression data in this example includes five consecutive “00h”, followed by “41h” and “4h”.
2h, followed by three consecutive "43h." In such pre-compression data, only "00h" of the continuous data is compressed to obtain post-compression data.

That is, this compressed data indicates that the first data "00h" has five data in the next data "05h", and the next data "05h" has uncompressed data "41h" and "42h". ”,“ 43h ”,“ 43h ”
, "43h" continue five times.

FIG. 3 is a schematic block diagram showing a data expanding function in the printer 2 of FIG. The data stored in the reception buffer 12A of the RAM 12
The bus 17 is controlled by the external memory controller 151 of C15.
Is read out one byte at a time, and the first data is 1s
The data is analyzed by the t data analysis unit 152. Then, the transfer destination address register 154 of the block transfer unit 153 or the block transfer counter 1 according to the analysis result.
The data processed by the function 55 is transferred to the external memory controller 151 via the bus 17 in units of R bytes.
The data is written to the image buffer 12C of the AM 12.

An operation example of such a configuration will be described with reference to the flowchart of FIG. First, the first data is acquired, and it is determined whether "00h" is continuous data from the first data (step S11,
S12). If "00h" is continuous data, the continuous number data is obtained (step S13), and the address is added (step S14).

On the other hand, in step S12, "00h"
If is not continuous data, the data is expanded into blocks (step S15). Next, it is determined whether or not raster development has been completed (step S16). If raster development has not been completed, the process returns to step S11, and the above-described processing is repeated. finish.

For example, in the case of the compressed data shown in FIG. 2, first, the first underlined first data "00h" is obtained. In this case, since the first data indicates that “00h” is continuous data, the next consecutive number data “0”
5h "is acquired, and the address of 5 is added.

Next, the second underlined first data "0"
In this case, since it is found that five uncompressed data continue from the first data in this case, each data "41h", "42h", "43h", "43h" is obtained.
, “43h” are expanded into blocks. As described above, FIG.
Can be expanded to the pre-compression data.

As described above, the present invention has been described with respect to specific embodiments. However, the present invention is not limited to these embodiments, and is applicable to other embodiments within the scope of the invention described in the claims. You. For example, in the above-described embodiment, the data to be compressed is described as non-print data "00h". However, the same effect can be obtained with one-color print data "FFh", so-called solid data.

In the above-described embodiment, when the data to be compressed is continuous, the data to be compressed and the data representing the number of continuations are arranged in order, and when the data other than the compressed data is continuous, the number of continuations is reduced. Although the data to be represented and the data other than the compressed data are arranged in order, the same effects can be obtained without adding the data in the order described above, for example, by adding a predetermined identifier or the like.

[0037]

As described above, according to the present invention,
Since only specific data needs to be compressed and decompressed, it is much simpler than before, and data compression and
Deployment can be easily realized. By using such a compression / expansion technique for a printer, the compressed print data received from the host can be expanded at a high speed, and the printing speed can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of a printer according to an embodiment of the present invention.

FIG. 2 is a diagram showing a specific example for describing a data compression method according to the embodiment of the present invention.

FIG. 3 is a schematic block diagram showing a data expanding function in the printer of FIG. 1;

FIG. 4 is a flowchart illustrating an operation example of a data expansion function of FIG. 3;

FIG. 5 is a schematic block diagram showing a general computer system connecting a PC as a host and a printer.

FIG. 6 is a diagram showing a specific example for explaining a conventional data compression method.

FIG. 7 is a schematic block diagram showing a data development function in a conventional printer.

FIG. 8 is a flowchart showing an operation example of a data expanding function of FIG. 7;

[Explanation of symbols]

 1 Host Computer 10 Printer Controller 11 Host I / F 12 RAM 12A Receive Buffer 12C Image Buffer 12B Work Memory 13 ROM 13a Main Program 13b Interrupt Processing Program 14 CPU 15 ASIC 151 External Memory Controller 152 1st Data Analysis Unit 153 Block Transfer Unit 154 Transfer destination address register 155 Block transfer counter 16 Mechanical I / F 17 Bus 20 Print engine 22 Print head 24 Carriage mechanism 26 Paper feed mechanism 100 PC 102 Printer driver 104 Operating system (OS) 106 I / F section of PC 100 115 Connection cable 200 Printer 220 I / F control unit 222 Data reception unit 224 Data transmission unit 230 Printing unit 231 Receiving buffer memory section 233 Command interpreting section 235 Image data expanding section 237 Print processing executing section 239 Status check 240 Receiving buffer 250 CPU 251 Header data analyzing section 252 Data transfer unit 260 Image buffer

Claims (10)

[Claims] 1. A method of compressing data, wherein, when specific data is continuous, one specific data and data representing the number of continuous data are arranged, and when data other than the specific data is continuous, A data compression method, comprising compressing data by arranging data representing the number of continuations and data other than the specific data. 2. A method for compressing data, wherein, when specific data is continuous, one specific data and data representing the number of continuations are arranged in order, and when data other than the specific data is continuous, A data compression method comprising compressing data by sequentially arranging data representing the number of continuations and data other than the specific data. 3. The data compression method according to claim 1, wherein the specific data is non-print data or one-color print data. 4. A method for expanding data, comprising: obtaining first data; and when the first data is specific data, obtaining data representing a continuous number of the next specific data and adding an address. When the first data is data other than the specific data, the data is developed by performing block development on data corresponding to the continuous number represented by the specific data. 5. The data expanding method according to claim 4, wherein the specific data is non-print data or one-color print data. 6. A printer comprising: an interface unit for receiving data from a host; and a printing unit for performing a predetermined print process based on the data received from the host. Acquired, and when the first data is specific data,
By obtaining data representing the number of consecutive specified data and adding an address, and when the first data is data other than the specified data, by expanding blocks of data corresponding to the number of consecutive data represented by the data, A printer comprising data expanding means for expanding data. 7. The printer according to claim 6, wherein the data development unit is provided in a semiconductor integrated circuit (ASIC) for a specific application. 8. The printer according to claim 6, wherein the specific data is non-print data or one-color print data. 9. The data received from the host, when specific data is continuous, arranges one specific data and data indicating the number of continuations, and when data other than the specific data is continuous, 9. Data compression is performed by arranging data representing the number of continuations and data other than the specific data.
Printer according to. 10. The data received from the host, when specific data is continuous, arranges one specific data and data representing the number of consecutive data in order, and when data other than the specific data is continuous, The data is compressed by sequentially arranging data representing the number of continuations and data other than the specific data.
9. The printer according to 7 or 8.